The helper used by the core-mm to strip tag bits and get the address to
the canonical shape. In only handles userspace addresses.

For LAM, the address gets sanitized according to the thread flags.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 arch/x86/include/asm/page_32.h |  3 +++
 arch/x86/include/asm/page_64.h | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/arch/x86/include/asm/page_32.h b/arch/x86/include/asm/page_32.h
index 94dbd51df58f..a829c46ab977 100644
--- a/arch/x86/include/asm/page_32.h
+++ b/arch/x86/include/asm/page_32.h
@@ -15,6 +15,9 @@ extern unsigned long __phys_addr(unsigned long);
 #define __phys_addr_symbol(x)  __phys_addr(x)
 #define __phys_reloc_hide(x)   RELOC_HIDE((x), 0)
 
+#define untagged_addr(addr)    (addr)
+#define untagged_ptr(ptr)      (ptr)
+
 #ifdef CONFIG_FLATMEM
 #define pfn_valid(pfn)         ((pfn) < max_mapnr)
 #endif /* CONFIG_FLATMEM */
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 939b1cff4a7b..67cb434efdf6 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -56,6 +56,25 @@ static inline void clear_page(void *page)
 
 void copy_page(void *to, void *from);
 
+#define __untagged_addr(addr, n)       \
+       ((__force __typeof__(addr))sign_extend64((__force u64)(addr), n))
+
+#define untagged_addr(addr)    ({                                      \
+       u64 __addr = (__force u64)(addr);                               \
+       if (__addr >> 63 == 0) {                                        \
+               if (test_thread_flag(TIF_LAM_U57))                      \
+                       __addr &= __untagged_addr(__addr, 56);          \
+               else if (test_thread_flag(TIF_LAM_U48))                 \
+                       __addr &= __untagged_addr(__addr, 47);          \
+       }                                                               \
+       (__force __typeof__(addr))__addr;                               \
+})
+
+#define untagged_ptr(ptr)      ({                                      \
+       u64 __ptrval = (__force u64)(ptr);                              \
+       __ptrval = untagged_addr(__ptrval);                             \
+       (__force __typeof__(*(ptr)) *)__ptrval;                         \
+})
 #endif /* !__ASSEMBLY__ */
 
 #ifdef CONFIG_X86_VSYSCALL_EMULATION
-- 
2.26.2

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